intervene

1[intransitive]to become involved in a situation in order to improve or help itShe might have been killed if the neighbors hadn't intervened.intervene in somethingThe President intervened personally in the crisis.

2[transitive,intransitive](+ speech)to interrupt someone when they are speaking in order to say something“But,” she intervened, “what about the others?”

3[intransitive]to happen in a way that delays something or prevents it from happeningThey were planning to get married and then the war intervened.

4[intransitive](formal)to exist between two events or placesI saw nothing of her during the years that intervened.